Physics Letters B 802 (2020) 135200
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Isomer studies in the vicinity of the doubly-magic nucleus
100
Sn:
Observation of a new low-lying isomeric state in
97
Ag
Christine Hornung
a,∗
, Daler Amanbayev
a
, Irene Dedes
b
, Gabriella Kripko-Koncz
a
,
Ivan Miskun
a
, Noritaka Shimizu
c
, Samuel Ayet San Andrés
a,d
, Julian Bergmann
a
,
Timo Dickel
a,d
, Jerzy Dudek
e,b
, Jens Ebert
a
, Hans Geissel
a,d
, Magdalena Górska
d
,
Hubert Grawe
d
, Florian Greiner
a
, Emma Haettner
d
, Takaharu Otsuka
f
, Wolfgang
R. Plaß
a,d
, Sivaji Purushothaman
d
, Ann-Kathrin Rink
a
, Christoph Scheidenberger
a,d
,
Helmut Weick
d
, Soumya Bagchi
a,d,g
, Andrey Blazhev
h
, Olga Charviakova
i
,
Dominique Curien
e
, Andrew Finlay
j
, Satbir Kaur
g
, Wayne Lippert
a
, Jan-Hendrik Otto
a
,
Zygmunt Patyk
i
, Stephane Pietri
d
, Yoshiki K. Tanaka
d
, Yusuke Tsunoda
c
, John S. Winfield
d
a
II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
b
Institute of Physics, Marie Curie-Sklodowska University, PL-20 031 Lublin, Poland
c
Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
d
GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
e
Université de Strasbourg, CNRS, IPHC UMR 7178, F-67 000 Strasbourg, France
f
RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
g
Saint Mary’s University, NS B3H 3C3 Halifax, Canada
h
Institut für Kernphysik, Universität zu Köln, D-50937 Köln, Germany
i
National Centre for Nuclear Research, Ho ˙za 69, 00-681 Warszawa, Poland
j
TRIUMF, BC V6T 2A3 Vancouver, Canada
a r t i c l e i n f o a b s t r a c t
Article history:
Received
30 September 2019
Received
in revised form 23 December 2019
Accepted
2 January 2020
Available
online 8 January 2020
Editor:
D.F. Geesaman
Keywords:
Mass
spectrometry
Multiple-reflection
time-of-flight mass
spectrometry
Nuclear
structure
Isomers
Isomer-to-ground
state ratio
Exotic
nuclei
Long-lived isomeric states in
97
Ag and
101−109
In were investigated with the FRS Ion Catcher at GSI.
In the isotope
97
Ag, a long-lived
1/2
−
isomeric state was discovered, and its excitation energy was
determined to be 618(38) keV. This is simultaneously the first discovery of a nuclear isomeric state by
multiple-reflection time-of-flight mass spectrometry. The measured excitation energies were compared
to large-scale shell-model calculations, which indicated the importance of core excitation around
100
Sn.
Furthermore, advanced mean-field calculations for the
97
Ag nucleus and relevant neighboring nuclei were
performed, which have contributed to a better understanding of the repetitive appearance of certain
isomeric structures in neighboring nuclei, and which have supported the discovery of the isomeric state
in
97
Ag in a global shell-evolution scheme.
© 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP
3
.
1. Introduction
The lifetimes of isomers are much longer than those of common
excited states [1]. There are several reasons for this: the shape, the
spin, or the spin orientation relative to a symmetry axis of the iso-
meric
state. The properties of nuclear isomers [2]are significant for
*
Corresponding author.
E-mail
address: c.hornung@gsi.de (C. Hornung).
the understanding of nuclear structure because they provide strin-
gent
tests for nuclear models. There is a broad field of applications
for nuclear isomers, ranging from new possibilities for the storage
of energy to the impact on nuclear astrophysics and the synthesis
of the elements in the universe [3].
The
nucleus
100
Sn is the heaviest self-conjugate doubly-magic
nucleus in the chart of nuclides, and therefore, attracts a broad in-
terest
in both experimental and theoretical nuclear physics. Since
its discovery [4,5], it has been the subject of many investigations
https://doi.org/10.1016/j.physletb.2020.135200
0370-2693/
© 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP
3
.